annotate mercurial/help/config.txt @ 26623:5a95fe44121d

clonebundles: support for seeding clones from pre-generated bundles

Cloning can be an expensive operation for servers because the server
generates a bundle from existing repository data at request time. For
a large repository like mozilla-central, this consumes 4+ minutes
of CPU time on the server. It also results in significant network
utilization. Multiplied by hundreds or even thousands of clients and
the ensuing load can result in difficulties scaling the Mercurial server.

Despite generation of bundles being deterministic until the next
changeset is added, the generation of bundles to service a clone request
is not cached. Each clone thus performs redundant work. This is
wasteful.

This patch introduces the "clonebundles" extension and related
client-side functionality to help alleviate this deficiency. The
client-side feature is behind an experimental flag and is not enabled by
default.

It works as follows:

1) Server operator generates a bundle and makes it available on a
   server (likely HTTP).
2) Server operator defines the URL of a bundle file in a
   .hg/clonebundles.manifest file.
3) Client `hg clone`ing sees the server is advertising bundle URLs.
4) Client fetches and applies the advertised bundle.
5) Client performs equivalent of `hg pull` to fetch changes made since
   the bundle was created.

Essentially, the server performs the expensive work of generating a
bundle once and all subsequent clones fetch a static file from
somewhere. Scaling static file serving is a much more manageable
problem than scaling a Python application like Mercurial. Assuming your
repository grows less than 1% per day, the end result is 99+% of CPU
and network load from clones is eliminated, allowing Mercurial servers
to scale more easily. Serving static files also means data can be
transferred to clients as fast as they can consume it, rather than as
fast as servers can generate it. This makes clones faster.

Mozilla has implemented similar functionality of this patch on
hg.mozilla.org using a custom extension. We are hosting bundle files in
Amazon S3 and CloudFront (a CDN) and have successfully offloaded
>1 TB/day in data transfer from hg.mozilla.org, freeing up significant
bandwidth and CPU resources. The positive impact has been stellar and
I believe it has proved its value to be included in Mercurial core. I
feel it is important for the client-side support to be enabled in core
by default because it means that clients will get faster, more reliable
clones and will enable server operators to reduce load without
requiring any client-side configuration changes (assuming clients are
up to date, of course).

The scope of this feature is narrowly and specifically tailored to
cloning, despite "serve pulls from pre-generated bundles" being a valid
and useful feature. I would eventually like for Mercurial servers to
support transferring *all* repository data via statically hosted files.
You could imagine a server that siphons all pushed data to bundle files
and instructs clients to apply a stream of bundles to reconstruct all
repository data. This feature, while useful and powerful, is
significantly more work to implement because it requires the server
component have awareness of discovery and a mapping of which changesets
are in which files. Full, clone bundles, by contrast, are much simpler.

The wire protocol command is named "clonebundles" instead of something
more generic like "staticbundles" to leave the door open for a new, more
powerful and more generic server-side component with minimal backwards
compatibility implications. The name "bundleclone" is used by Mozilla's
extension and would cause problems since there are subtle differences
in Mozilla's extension.

Mozilla's experience with this idea has taught us that some form of
"content negotiation" is required. Not all clients will support all
bundle formats or even URLs (advanced TLS requirements, etc). To ensure
the highest uptake possible, a server needs to advertise multiple
versions of bundles and clients need to be able to choose the most
appropriate from that list one. The "attributes" in each
server-advertised entry facilitate this filtering and sorting. Their
use will become apparent in subsequent patches.

Initial inspiration and credit for the idea of cloning from static files
belongs to Augie Fackler and his "lookaside clone" extension proof of
concept.

The Mercurial system uses a set of configuration files to control
aspects of its behavior.

Troubleshooting
===============

If you're having problems with your configuration,
:hg:`config --debug` can help you understand what is introducing
a setting into your environment.

See :hg:`help config.syntax` and :hg:`help config.files`
for information about how and where to override things.

Format
======

The configuration files use a simple ini-file format. A configuration
file consists of sections, led by a ``[section]`` header and followed
by ``name = value`` entries::

  [ui]
  username = Firstname Lastname <[e-mail]>
  verbose = True

The above entries will be referred to as ``ui.username`` and
``ui.verbose``, respectively. See :hg:`help config.syntax`.

Files
=====

Mercurial reads configuration data from several files, if they exist.
These files do not exist by default and you will have to create the
appropriate configuration files yourself: global configuration like
the username setting is typically put into
``%USERPROFILE%\mercurial.ini`` or ``$HOME/.hgrc`` and local
configuration is put into the per-repository ``<repo>/.hg/hgrc`` file.

The names of these files depend on the system on which Mercurial is
installed. ``*.rc`` files from a single directory are read in
alphabetical order, later ones overriding earlier ones. Where multiple
paths are given below, settings from earlier paths override later
ones.

.. container:: verbose.unix

  On Unix, the following files are consulted:

  - ``<repo>/.hg/hgrc`` (per-repository)
  - ``$HOME/.hgrc`` (per-user)
  - ``<install-root>/etc/mercurial/hgrc`` (per-installation)
  - ``<install-root>/etc/mercurial/hgrc.d/*.rc`` (per-installation)
  - ``/etc/mercurial/hgrc`` (per-system)
  - ``/etc/mercurial/hgrc.d/*.rc`` (per-system)
  - ``<internal>/default.d/*.rc`` (defaults)

.. container:: verbose.windows

  On Windows, the following files are consulted:

  - ``<repo>/.hg/hgrc`` (per-repository)
  - ``%USERPROFILE%\.hgrc`` (per-user)
  - ``%USERPROFILE%\Mercurial.ini`` (per-user)
  - ``%HOME%\.hgrc`` (per-user)
  - ``%HOME%\Mercurial.ini`` (per-user)
  - ``<install-dir>\Mercurial.ini`` (per-installation)
  - ``<install-dir>\hgrc.d\*.rc`` (per-installation)
  - ``HKEY_LOCAL_MACHINE\SOFTWARE\Mercurial`` (per-installation)
  - ``<internal>/default.d/*.rc`` (defaults)

  .. note::

   The registry key ``HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Mercurial``
   is used when running 32-bit Python on 64-bit Windows.

.. container:: verbose.plan9

  On Plan9, the following files are consulted:

  - ``<repo>/.hg/hgrc`` (per-repository)
  - ``$home/lib/hgrc`` (per-user)
  - ``<install-root>/lib/mercurial/hgrc`` (per-installation)
  - ``<install-root>/lib/mercurial/hgrc.d/*.rc`` (per-installation)
  - ``/lib/mercurial/hgrc`` (per-system)
  - ``/lib/mercurial/hgrc.d/*.rc`` (per-system)
  - ``<internal>/default.d/*.rc`` (defaults)

Per-repository configuration options only apply in a
particular repository. This file is not version-controlled, and
will not get transferred during a "clone" operation. Options in
this file override options in all other configuration files. On
Plan 9 and Unix, most of this file will be ignored if it doesn't
belong to a trusted user or to a trusted group. See
:hg:`help config.trusted` for more details.

Per-user configuration file(s) are for the user running Mercurial. On
Windows 9x, ``%HOME%`` is replaced by ``%APPDATA%``. Options in these
files apply to all Mercurial commands executed by this user in any
directory. Options in these files override per-system and per-installation
options.

Per-installation configuration files are searched for in the
directory where Mercurial is installed. ``<install-root>`` is the
parent directory of the **hg** executable (or symlink) being run. For
example, if installed in ``/shared/tools/bin/hg``, Mercurial will look
in ``/shared/tools/etc/mercurial/hgrc``. Options in these files apply
to all Mercurial commands executed by any user in any directory.

Per-installation configuration files are for the system on
which Mercurial is running. Options in these files apply to all
Mercurial commands executed by any user in any directory. Registry
keys contain PATH-like strings, every part of which must reference
a ``Mercurial.ini`` file or be a directory where ``*.rc`` files will
be read.  Mercurial checks each of these locations in the specified
order until one or more configuration files are detected.

Per-system configuration files are for the system on which Mercurial
is running. Options in these files apply to all Mercurial commands
executed by any user in any directory. Options in these files
override per-installation options.

Mercurial comes with some default configuration. The default configuration
files are installed with Mercurial and will be overwritten on upgrades. Default
configuration files should never be edited by users or administrators but can
be overridden in other configuration files. So far the directory only contains
merge tool configuration but packagers can also put other default configuration
there.

Syntax
======

A configuration file consists of sections, led by a ``[section]`` header
and followed by ``name = value`` entries (sometimes called
``configuration keys``)::

    [spam]
    eggs=ham
    green=
       eggs

Each line contains one entry. If the lines that follow are indented,
they are treated as continuations of that entry. Leading whitespace is
removed from values. Empty lines are skipped. Lines beginning with
``#`` or ``;`` are ignored and may be used to provide comments.

Configuration keys can be set multiple times, in which case Mercurial
will use the value that was configured last. As an example::

    [spam]
    eggs=large
    ham=serrano
    eggs=small

This would set the configuration key named ``eggs`` to ``small``.

It is also possible to define a section multiple times. A section can
be redefined on the same and/or on different configuration files. For
example::

    [foo]
    eggs=large
    ham=serrano
    eggs=small

    [bar]
    eggs=ham
    green=
       eggs

    [foo]
    ham=prosciutto
    eggs=medium
    bread=toasted

This would set the ``eggs``, ``ham``, and ``bread`` configuration keys
of the ``foo`` section to ``medium``, ``prosciutto``, and ``toasted``,
respectively. As you can see there only thing that matters is the last
value that was set for each of the configuration keys.

If a configuration key is set multiple times in different
configuration files the final value will depend on the order in which
the different configuration files are read, with settings from earlier
paths overriding later ones as described on the ``Files`` section
above.

A line of the form ``%include file`` will include ``file`` into the
current configuration file. The inclusion is recursive, which means
that included files can include other files. Filenames are relative to
the configuration file in which the ``%include`` directive is found.
Environment variables and ``~user`` constructs are expanded in
``file``. This lets you do something like::

  %include ~/.hgrc.d/$HOST.rc

to include a different configuration file on each computer you use.

A line with ``%unset name`` will remove ``name`` from the current
section, if it has been set previously.

The values are either free-form text strings, lists of text strings,
or Boolean values. Boolean values can be set to true using any of "1",
"yes", "true", or "on" and to false using "0", "no", "false", or "off"
(all case insensitive).

List values are separated by whitespace or comma, except when values are
placed in double quotation marks::

  allow_read = "John Doe, PhD", brian, betty

Quotation marks can be escaped by prefixing them with a backslash. Only
quotation marks at the beginning of a word is counted as a quotation
(e.g., ``foo"bar baz`` is the list of ``foo"bar`` and ``baz``).

Sections
========

This section describes the different sections that may appear in a
Mercurial configuration file, the purpose of each section, its possible
keys, and their possible values.

``alias``
---------

Defines command aliases.

Aliases allow you to define your own commands in terms of other
commands (or aliases), optionally including arguments. Positional
arguments in the form of ``$1``, ``$2``, etc. in the alias definition
are expanded by Mercurial before execution. Positional arguments not
already used by ``$N`` in the definition are put at the end of the
command to be executed.

Alias definitions consist of lines of the form::

    <alias> = <command> [<argument>]...

For example, this definition::

    latest = log --limit 5

creates a new command ``latest`` that shows only the five most recent
changesets. You can define subsequent aliases using earlier ones::

    stable5 = latest -b stable

.. note::

   It is possible to create aliases with the same names as
   existing commands, which will then override the original
   definitions. This is almost always a bad idea!

An alias can start with an exclamation point (``!``) to make it a
shell alias. A shell alias is executed with the shell and will let you
run arbitrary commands. As an example, ::

   echo = !echo $@

will let you do ``hg echo foo`` to have ``foo`` printed in your
terminal. A better example might be::

   purge = !$HG status --no-status --unknown -0 | xargs -0 rm

which will make ``hg purge`` delete all unknown files in the
repository in the same manner as the purge extension.

Positional arguments like ``$1``, ``$2``, etc. in the alias definition
expand to the command arguments. Unmatched arguments are
removed. ``$0`` expands to the alias name and ``$@`` expands to all
arguments separated by a space. ``"$@"`` (with quotes) expands to all
arguments quoted individually and separated by a space. These expansions
happen before the command is passed to the shell.

Shell aliases are executed in an environment where ``$HG`` expands to
the path of the Mercurial that was used to execute the alias. This is
useful when you want to call further Mercurial commands in a shell
alias, as was done above for the purge alias. In addition,
``$HG_ARGS`` expands to the arguments given to Mercurial. In the ``hg
echo foo`` call above, ``$HG_ARGS`` would expand to ``echo foo``.

.. note::

   Some global configuration options such as ``-R`` are
   processed before shell aliases and will thus not be passed to
   aliases.


``annotate``
------------

Settings used when displaying file annotations. All values are
Booleans and default to False. See :hg:`help config.diff` for
related options for the diff command.

``ignorews``
    Ignore white space when comparing lines.

``ignorewsamount``
    Ignore changes in the amount of white space.

``ignoreblanklines``
    Ignore changes whose lines are all blank.


``auth``
--------

Authentication credentials for HTTP authentication. This section
allows you to store usernames and passwords for use when logging
*into* HTTP servers. See :hg:`help config.web` if
you want to configure *who* can login to your HTTP server.

Each line has the following format::

    <name>.<argument> = <value>

where ``<name>`` is used to group arguments into authentication
entries. Example::

    foo.prefix = hg.intevation.org/mercurial
    foo.username = foo
    foo.password = bar
    foo.schemes = http https

    bar.prefix = secure.example.org
    bar.key = path/to/file.key
    bar.cert = path/to/file.cert
    bar.schemes = https

Supported arguments:

``prefix``
    Either ``*`` or a URI prefix with or without the scheme part.
    The authentication entry with the longest matching prefix is used
    (where ``*`` matches everything and counts as a match of length
    1). If the prefix doesn't include a scheme, the match is performed
    against the URI with its scheme stripped as well, and the schemes
    argument, q.v., is then subsequently consulted.

``username``
    Optional. Username to authenticate with. If not given, and the
    remote site requires basic or digest authentication, the user will
    be prompted for it. Environment variables are expanded in the
    username letting you do ``foo.username = $USER``. If the URI
    includes a username, only ``[auth]`` entries with a matching
    username or without a username will be considered.

``password``
    Optional. Password to authenticate with. If not given, and the
    remote site requires basic or digest authentication, the user
    will be prompted for it.

``key``
    Optional. PEM encoded client certificate key file. Environment
    variables are expanded in the filename.

``cert``
    Optional. PEM encoded client certificate chain file. Environment
    variables are expanded in the filename.

``schemes``
    Optional. Space separated list of URI schemes to use this
    authentication entry with. Only used if the prefix doesn't include
    a scheme. Supported schemes are http and https. They will match
    static-http and static-https respectively, as well.
    (default: https)

If no suitable authentication entry is found, the user is prompted
for credentials as usual if required by the remote.


``committemplate``
------------------

``changeset``
    String: configuration in this section is used as the template to
    customize the text shown in the editor when committing.

In addition to pre-defined template keywords, commit log specific one
below can be used for customization:

``extramsg``
    String: Extra message (typically 'Leave message empty to abort
    commit.'). This may be changed by some commands or extensions.

For example, the template configuration below shows as same text as
one shown by default::

    [committemplate]
    changeset = {desc}\n\n
        HG: Enter commit message.  Lines beginning with 'HG:' are removed.
        HG: {extramsg}
        HG: --
        HG: user: {author}\n{ifeq(p2rev, "-1", "",
       "HG: branch merge\n")
       }HG: branch '{branch}'\n{if(activebookmark,
       "HG: bookmark '{activebookmark}'\n")   }{subrepos %
       "HG: subrepo {subrepo}\n"              }{file_adds %
       "HG: added {file}\n"                   }{file_mods %
       "HG: changed {file}\n"                 }{file_dels %
       "HG: removed {file}\n"                 }{if(files, "",
       "HG: no files changed\n")}

.. note::

   For some problematic encodings (see :hg:`help win32mbcs` for
   detail), this customization should be configured carefully, to
   avoid showing broken characters.

   For example, if a multibyte character ending with backslash (0x5c) is
   followed by the ASCII character 'n' in the customized template,
   the sequence of backslash and 'n' is treated as line-feed unexpectedly
   (and the multibyte character is broken, too).

Customized template is used for commands below (``--edit`` may be
required):

- :hg:`backout`
- :hg:`commit`
- :hg:`fetch` (for merge commit only)
- :hg:`graft`
- :hg:`histedit`
- :hg:`import`
- :hg:`qfold`, :hg:`qnew` and :hg:`qrefresh`
- :hg:`rebase`
- :hg:`shelve`
- :hg:`sign`
- :hg:`tag`
- :hg:`transplant`

Configuring items below instead of ``changeset`` allows showing
customized message only for specific actions, or showing different
messages for each action.

- ``changeset.backout`` for :hg:`backout`
- ``changeset.commit.amend.merge`` for :hg:`commit --amend` on merges
- ``changeset.commit.amend.normal`` for :hg:`commit --amend` on other
- ``changeset.commit.normal.merge`` for :hg:`commit` on merges
- ``changeset.commit.normal.normal`` for :hg:`commit` on other
- ``changeset.fetch`` for :hg:`fetch` (impling merge commit)
- ``changeset.gpg.sign`` for :hg:`sign`
- ``changeset.graft`` for :hg:`graft`
- ``changeset.histedit.edit`` for ``edit`` of :hg:`histedit`
- ``changeset.histedit.fold`` for ``fold`` of :hg:`histedit`
- ``changeset.histedit.mess`` for ``mess`` of :hg:`histedit`
- ``changeset.histedit.pick`` for ``pick`` of :hg:`histedit`
- ``changeset.import.bypass`` for :hg:`import --bypass`
- ``changeset.import.normal.merge`` for :hg:`import` on merges
- ``changeset.import.normal.normal`` for :hg:`import` on other
- ``changeset.mq.qnew`` for :hg:`qnew`
- ``changeset.mq.qfold`` for :hg:`qfold`
- ``changeset.mq.qrefresh`` for :hg:`qrefresh`
- ``changeset.rebase.collapse`` for :hg:`rebase --collapse`
- ``changeset.rebase.merge`` for :hg:`rebase` on merges
- ``changeset.rebase.normal`` for :hg:`rebase` on other
- ``changeset.shelve.shelve`` for :hg:`shelve`
- ``changeset.tag.add`` for :hg:`tag` without ``--remove``
- ``changeset.tag.remove`` for :hg:`tag --remove`
- ``changeset.transplant.merge`` for :hg:`transplant` on merges
- ``changeset.transplant.normal`` for :hg:`transplant` on other

These dot-separated lists of names are treated as hierarchical ones.
For example, ``changeset.tag.remove`` customizes the commit message
only for :hg:`tag --remove`, but ``changeset.tag`` customizes the
commit message for :hg:`tag` regardless of ``--remove`` option.

When the external editor is invoked for a commit, the corresponding
dot-separated list of names without the ``changeset.`` prefix
(e.g. ``commit.normal.normal``) is in the ``HGEDITFORM`` environment
variable.

In this section, items other than ``changeset`` can be referred from
others. For example, the configuration to list committed files up
below can be referred as ``{listupfiles}``::

    [committemplate]
    listupfiles = {file_adds %
       "HG: added {file}\n"     }{file_mods %
       "HG: changed {file}\n"   }{file_dels %
       "HG: removed {file}\n"   }{if(files, "",
       "HG: no files changed\n")}

``decode/encode``
-----------------

Filters for transforming files on checkout/checkin. This would
typically be used for newline processing or other
localization/canonicalization of files.

Filters consist of a filter pattern followed by a filter command.
Filter patterns are globs by default, rooted at the repository root.
For example, to match any file ending in ``.txt`` in the root
directory only, use the pattern ``*.txt``. To match any file ending
in ``.c`` anywhere in the repository, use the pattern ``**.c``.
For each file only the first matching filter applies.

The filter command can start with a specifier, either ``pipe:`` or
``tempfile:``. If no specifier is given, ``pipe:`` is used by default.

A ``pipe:`` command must accept data on stdin and return the transformed
data on stdout.

Pipe example::

  [encode]
  # uncompress gzip files on checkin to improve delta compression
  # note: not necessarily a good idea, just an example
  *.gz = pipe: gunzip

  [decode]
  # recompress gzip files when writing them to the working dir (we
  # can safely omit "pipe:", because it's the default)
  *.gz = gzip

A ``tempfile:`` command is a template. The string ``INFILE`` is replaced
with the name of a temporary file that contains the data to be
filtered by the command. The string ``OUTFILE`` is replaced with the name
of an empty temporary file, where the filtered data must be written by
the command.

.. note::

   The tempfile mechanism is recommended for Windows systems,
   where the standard shell I/O redirection operators often have
   strange effects and may corrupt the contents of your files.

This filter mechanism is used internally by the ``eol`` extension to
translate line ending characters between Windows (CRLF) and Unix (LF)
format. We suggest you use the ``eol`` extension for convenience.


``defaults``
------------

(defaults are deprecated. Don't use them. Use aliases instead.)

Use the ``[defaults]`` section to define command defaults, i.e. the
default options/arguments to pass to the specified commands.

The following example makes :hg:`log` run in verbose mode, and
:hg:`status` show only the modified files, by default::

  [defaults]
  log = -v
  status = -m

The actual commands, instead of their aliases, must be used when
defining command defaults. The command defaults will also be applied
to the aliases of the commands defined.


``diff``
--------

Settings used when displaying diffs. Everything except for ``unified``
is a Boolean and defaults to False. See :hg:`help config.annotate`
for related options for the annotate command.

``git``
    Use git extended diff format.

``nobinary``
    Omit git binary patches.

``nodates``
    Don't include dates in diff headers.

``noprefix``
    Omit 'a/' and 'b/' prefixes from filenames. Ignored in plain mode.

``showfunc``
    Show which function each change is in.

``ignorews``
    Ignore white space when comparing lines.

``ignorewsamount``
    Ignore changes in the amount of white space.

``ignoreblanklines``
    Ignore changes whose lines are all blank.

``unified``
    Number of lines of context to show.

``email``
---------

Settings for extensions that send email messages.

``from``
    Optional. Email address to use in "From" header and SMTP envelope
    of outgoing messages.

``to``
    Optional. Comma-separated list of recipients' email addresses.

``cc``
    Optional. Comma-separated list of carbon copy recipients'
    email addresses.

``bcc``
    Optional. Comma-separated list of blind carbon copy recipients'
    email addresses.

``method``
    Optional. Method to use to send email messages. If value is ``smtp``
    (default), use SMTP (see the ``[smtp]`` section for configuration).
    Otherwise, use as name of program to run that acts like sendmail
    (takes ``-f`` option for sender, list of recipients on command line,
    message on stdin). Normally, setting this to ``sendmail`` or
    ``/usr/sbin/sendmail`` is enough to use sendmail to send messages.

``charsets``
    Optional. Comma-separated list of character sets considered
    convenient for recipients. Addresses, headers, and parts not
    containing patches of outgoing messages will be encoded in the
    first character set to which conversion from local encoding
    (``$HGENCODING``, ``ui.fallbackencoding``) succeeds. If correct
    conversion fails, the text in question is sent as is.
    (default: '')

    Order of outgoing email character sets:

    1. ``us-ascii``: always first, regardless of settings
    2. ``email.charsets``: in order given by user
    3. ``ui.fallbackencoding``: if not in email.charsets
    4. ``$HGENCODING``: if not in email.charsets
    5. ``utf-8``: always last, regardless of settings

Email example::

  [email]
  from = Joseph User <[e-mail]>
  method = /usr/sbin/sendmail
  # charsets for western Europeans
  # us-ascii, utf-8 omitted, as they are tried first and last
  charsets = iso-8859-1, iso-8859-15, windows-1252


``extensions``
--------------

Mercurial has an extension mechanism for adding new features. To
enable an extension, create an entry for it in this section.

If you know that the extension is already in Python's search path,
you can give the name of the module, followed by ``=``, with nothing
after the ``=``.

Otherwise, give a name that you choose, followed by ``=``, followed by
the path to the ``.py`` file (including the file name extension) that
defines the extension.

To explicitly disable an extension that is enabled in an hgrc of
broader scope, prepend its path with ``!``, as in ``foo = !/ext/path``
or ``foo = !`` when path is not supplied.

Example for ``~/.hgrc``::

  [extensions]
  # (the color extension will get loaded from Mercurial's path)
  color =
  # (this extension will get loaded from the file specified)
  myfeature = ~/.hgext/myfeature.py


``format``
----------

``usestore``
    Enable or disable the "store" repository format which improves
    compatibility with systems that fold case or otherwise mangle
    filenames. Enabled by default. Disabling this option will allow
    you to store longer filenames in some situations at the expense of
    compatibility and ensures that the on-disk format of newly created
    repositories will be compatible with Mercurial before version 0.9.4.

``usefncache``
    Enable or disable the "fncache" repository format which enhances
    the "store" repository format (which has to be enabled to use
    fncache) to allow longer filenames and avoids using Windows
    reserved names, e.g. "nul". Enabled by default. Disabling this
    option ensures that the on-disk format of newly created
    repositories will be compatible with Mercurial before version 1.1.

``dotencode``
    Enable or disable the "dotencode" repository format which enhances
    the "fncache" repository format (which has to be enabled to use
    dotencode) to avoid issues with filenames starting with ._ on
    Mac OS X and spaces on Windows. Enabled by default. Disabling this
    option ensures that the on-disk format of newly created
    repositories will be compatible with Mercurial before version 1.7.

``graph``
---------

Web graph view configuration. This section let you change graph
elements display properties by branches, for instance to make the
``default`` branch stand out.

Each line has the following format::

    <branch>.<argument> = <value>

where ``<branch>`` is the name of the branch being
customized. Example::

    [graph]
    # 2px width
    default.width = 2
    # red color
    default.color = FF0000

Supported arguments:

``width``
    Set branch edges width in pixels.

``color``
    Set branch edges color in hexadecimal RGB notation.

``hooks``
---------

Commands or Python functions that get automatically executed by
various actions such as starting or finishing a commit. Multiple
hooks can be run for the same action by appending a suffix to the
action. Overriding a site-wide hook can be done by changing its
value or setting it to an empty string.  Hooks can be prioritized
by adding a prefix of ``priority`` to the hook name on a new line
and setting the priority. The default priority is 0.

Example ``.hg/hgrc``::

  [hooks]
  # update working directory after adding changesets
  changegroup.update = hg update
  # do not use the site-wide hook
  incoming =
  incoming.email = /my/email/hook
  incoming.autobuild = /my/build/hook
  # force autobuild hook to run before other incoming hooks
  priority.incoming.autobuild = 1

Most hooks are run with environment variables set that give useful
additional information. For each hook below, the environment
variables it is passed are listed with names of the form ``$HG_foo``.

``changegroup``
  Run after a changegroup has been added via push, pull or unbundle.
  ID of the first new changeset is in ``$HG_NODE``. URL from which
  changes came is in ``$HG_URL``.

``commit``
  Run after a changeset has been created in the local repository. ID
  of the newly created changeset is in ``$HG_NODE``. Parent changeset
  IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.

``incoming``
  Run after a changeset has been pulled, pushed, or unbundled into
  the local repository. The ID of the newly arrived changeset is in
  ``$HG_NODE``. URL that was source of changes came is in ``$HG_URL``.

``outgoing``
  Run after sending changes from local repository to another. ID of
  first changeset sent is in ``$HG_NODE``. Source of operation is in
  ``$HG_SOURCE``; Also see :hg:`help config.preoutgoing` hook.

``post-<command>``
  Run after successful invocations of the associated command. The
  contents of the command line are passed as ``$HG_ARGS`` and the result
  code in ``$HG_RESULT``. Parsed command line arguments are passed as
  ``$HG_PATS`` and ``$HG_OPTS``. These contain string representations of
  the python data internally passed to <command>. ``$HG_OPTS`` is a
  dictionary of options (with unspecified options set to their defaults).
  ``$HG_PATS`` is a list of arguments. Hook failure is ignored.

``pre-<command>``
  Run before executing the associated command. The contents of the
  command line are passed as ``$HG_ARGS``. Parsed command line arguments
  are passed as ``$HG_PATS`` and ``$HG_OPTS``. These contain string
  representations of the data internally passed to <command>. ``$HG_OPTS``
  is a  dictionary of options (with unspecified options set to their
  defaults). ``$HG_PATS`` is a list of arguments. If the hook returns
  failure, the command doesn't execute and Mercurial returns the failure
  code.

``prechangegroup``
  Run before a changegroup is added via push, pull or unbundle. Exit
  status 0 allows the changegroup to proceed. Non-zero status will
  cause the push, pull or unbundle to fail. URL from which changes
  will come is in ``$HG_URL``.

``precommit``
  Run before starting a local commit. Exit status 0 allows the
  commit to proceed. Non-zero status will cause the commit to fail.
  Parent changeset IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.

``prelistkeys``
  Run before listing pushkeys (like bookmarks) in the
  repository. Non-zero status will cause failure. The key namespace is
  in ``$HG_NAMESPACE``.

``preoutgoing``
  Run before collecting changes to send from the local repository to
  another. Non-zero status will cause failure. This lets you prevent
  pull over HTTP or SSH. Also prevents against local pull, push
  (outbound) or bundle commands, but not effective, since you can
  just copy files instead then. Source of operation is in
  ``$HG_SOURCE``. If "serve", operation is happening on behalf of remote
  SSH or HTTP repository. If "push", "pull" or "bundle", operation
  is happening on behalf of repository on same system.

``prepushkey``
  Run before a pushkey (like a bookmark) is added to the
  repository. Non-zero status will cause the key to be rejected. The
  key namespace is in ``$HG_NAMESPACE``, the key is in ``$HG_KEY``,
  the old value (if any) is in ``$HG_OLD``, and the new value is in
  ``$HG_NEW``.

``pretag``
  Run before creating a tag. Exit status 0 allows the tag to be
  created. Non-zero status will cause the tag to fail. ID of
  changeset to tag is in ``$HG_NODE``. Name of tag is in ``$HG_TAG``. Tag is
  local if ``$HG_LOCAL=1``, in repository if ``$HG_LOCAL=0``.

``pretxnopen``
  Run before any new repository transaction is open. The reason for the
  transaction will be in ``$HG_TXNNAME`` and a unique identifier for the
  transaction will be in ``HG_TXNID``. A non-zero status will prevent the
  transaction from being opened.

``pretxnclose``
  Run right before the transaction is actually finalized. Any
  repository change will be visible to the hook program. This lets you
  validate the transaction content or change it. Exit status 0 allows
  the commit to proceed. Non-zero status will cause the transaction to
  be rolled back. The reason for the transaction opening will be in
  ``$HG_TXNNAME`` and a unique identifier for the transaction will be in
  ``HG_TXNID``. The rest of the available data will vary according the
  transaction type. New changesets will add ``$HG_NODE`` (id of the
  first added changeset), ``$HG_URL`` and ``$HG_SOURCE`` variables,
  bookmarks and phases changes will set ``HG_BOOKMARK_MOVED`` and
  ``HG_PHASES_MOVED`` to ``1``, etc.

``txnclose``
  Run after any repository transaction has been committed. At this
  point, the transaction can no longer be rolled back. The hook will run
  after the lock is released. See :hg:`help config.pretxnclose` docs for
  details about available variables.

``txnabort``
  Run when a transaction is aborted. See :hg:`help config.pretxnclose`
  docs for details about available variables.

``pretxnchangegroup``
  Run after a changegroup has been added via push, pull or unbundle,
  but before the transaction has been committed. Changegroup is
  visible to hook program. This lets you validate incoming changes
  before accepting them. Passed the ID of the first new changeset in
  ``$HG_NODE``. Exit status 0 allows the transaction to commit. Non-zero
  status will cause the transaction to be rolled back and the push,
  pull or unbundle will fail. URL that was source of changes is in
  ``$HG_URL``.

``pretxncommit``
  Run after a changeset has been created but the transaction not yet
  committed. Changeset is visible to hook program. This lets you
  validate commit message and changes. Exit status 0 allows the
  commit to proceed. Non-zero status will cause the transaction to
  be rolled back. ID of changeset is in ``$HG_NODE``. Parent changeset
  IDs are in ``$HG_PARENT1`` and ``$HG_PARENT2``.

``preupdate``
  Run before updating the working directory. Exit status 0 allows
  the update to proceed. Non-zero status will prevent the update.
  Changeset ID of first new parent is in ``$HG_PARENT1``. If merge, ID
  of second new parent is in ``$HG_PARENT2``.

``listkeys``
  Run after listing pushkeys (like bookmarks) in the repository. The
  key namespace is in ``$HG_NAMESPACE``. ``$HG_VALUES`` is a
  dictionary containing the keys and values.

``pushkey``
  Run after a pushkey (like a bookmark) is added to the
  repository. The key namespace is in ``$HG_NAMESPACE``, the key is in
  ``$HG_KEY``, the old value (if any) is in ``$HG_OLD``, and the new
  value is in ``$HG_NEW``.

``tag``
  Run after a tag is created. ID of tagged changeset is in ``$HG_NODE``.
  Name of tag is in ``$HG_TAG``. Tag is local if ``$HG_LOCAL=1``, in
  repository if ``$HG_LOCAL=0``.

``update``
  Run after updating the working directory. Changeset ID of first
  new parent is in ``$HG_PARENT1``. If merge, ID of second new parent is
  in ``$HG_PARENT2``. If the update succeeded, ``$HG_ERROR=0``. If the
  update failed (e.g. because conflicts not resolved), ``$HG_ERROR=1``.

.. note::

   It is generally better to use standard hooks rather than the
   generic pre- and post- command hooks as they are guaranteed to be
   called in the appropriate contexts for influencing transactions.
   Also, hooks like "commit" will be called in all contexts that
   generate a commit (e.g. tag) and not just the commit command.

.. note::

   Environment variables with empty values may not be passed to
   hooks on platforms such as Windows. As an example, ``$HG_PARENT2``
   will have an empty value under Unix-like platforms for non-merge
   changesets, while it will not be available at all under Windows.

The syntax for Python hooks is as follows::

  hookname = python:modulename.submodule.callable
  hookname = python:/path/to/python/module.py:callable

Python hooks are run within the Mercurial process. Each hook is
called with at least three keyword arguments: a ui object (keyword
``ui``), a repository object (keyword ``repo``), and a ``hooktype``
keyword that tells what kind of hook is used. Arguments listed as
environment variables above are passed as keyword arguments, with no
``HG_`` prefix, and names in lower case.

If a Python hook returns a "true" value or raises an exception, this
is treated as a failure.


``hostfingerprints``
--------------------

Fingerprints of the certificates of known HTTPS servers.
A HTTPS connection to a server with a fingerprint configured here will
only succeed if the servers certificate matches the fingerprint.
This is very similar to how ssh known hosts works.
The fingerprint is the SHA-1 hash value of the DER encoded certificate.
The CA chain and web.cacerts is not used for servers with a fingerprint.

For example::

    [hostfingerprints]
    hg.intevation.org = fa:1f:d9:48:f1:e7:74:30:38:8d:d8:58:b6:94:b8:58:28:7d:8b:d0

This feature is only supported when using Python 2.6 or later.


``http_proxy``
--------------

Used to access web-based Mercurial repositories through a HTTP
proxy.

``host``
    Host name and (optional) port of the proxy server, for example
    "myproxy:8000".

``no``
    Optional. Comma-separated list of host names that should bypass
    the proxy.

``passwd``
    Optional. Password to authenticate with at the proxy server.

``user``
    Optional. User name to authenticate with at the proxy server.

``always``
    Optional. Always use the proxy, even for localhost and any entries
    in ``http_proxy.no``. (default: False)

``merge-patterns``
------------------

This section specifies merge tools to associate with particular file
patterns. Tools matched here will take precedence over the default
merge tool. Patterns are globs by default, rooted at the repository
root.

Example::

  [merge-patterns]
  **.c = kdiff3
  **.jpg = myimgmerge

``merge-tools``
---------------

This section configures external merge tools to use for file-level
merges. This section has likely been preconfigured at install time.
Use :hg:`config merge-tools` to check the existing configuration.
Also see :hg:`help merge-tools` for more details.

Example ``~/.hgrc``::

  [merge-tools]
  # Override stock tool location
  kdiff3.executable = ~/bin/kdiff3
  # Specify command line
  kdiff3.args = $base $local $other -o $output
  # Give higher priority
  kdiff3.priority = 1

  # Changing the priority of preconfigured tool
  vimdiff.priority = 0

  # Define new tool
  myHtmlTool.args = -m $local $other $base $output
  myHtmlTool.regkey = Software\FooSoftware\HtmlMerge
  myHtmlTool.priority = 1

Supported arguments:

``priority``
  The priority in which to evaluate this tool.
  (default: 0)

``executable``
  Either just the name of the executable or its pathname.  On Windows,
  the path can use environment variables with ${ProgramFiles} syntax.
  (default: the tool name)

``args``
  The arguments to pass to the tool executable. You can refer to the
  files being merged as well as the output file through these
  variables: ``$base``, ``$local``, ``$other``, ``$output``. The meaning
  of ``$local`` and ``$other`` can vary depending on which action is being
  performed. During and update or merge, ``$local`` represents the original
  state of the file, while ``$other`` represents the commit you are updating
  to or the commit you are merging with. During a rebase ``$local``
  represents the destination of the rebase, and ``$other`` represents the
  commit being rebased.
  (default: ``$local $base $other``)

``premerge``
  Attempt to run internal non-interactive 3-way merge tool before
  launching external tool.  Options are ``true``, ``false``, ``keep`` or
  ``keep-merge3``. The ``keep`` option will leave markers in the file if the
  premerge fails. The ``keep-merge3`` will do the same but include information
  about the base of the merge in the marker (see internal :merge3 in
  :hg:`help merge-tools`).
  (default: True)

``binary``
  This tool can merge binary files. (default: False, unless tool
  was selected by file pattern match)

``symlink``
  This tool can merge symlinks. (default: False)

``check``
  A list of merge success-checking options:

  ``changed``
    Ask whether merge was successful when the merged file shows no changes.
  ``conflicts``
    Check whether there are conflicts even though the tool reported success.
  ``prompt``
    Always prompt for merge success, regardless of success reported by tool.

``fixeol``
  Attempt to fix up EOL changes caused by the merge tool.
  (default: False)

``gui``
  This tool requires a graphical interface to run. (default: False)

``regkey``
  Windows registry key which describes install location of this
  tool. Mercurial will search for this key first under
  ``HKEY_CURRENT_USER`` and then under ``HKEY_LOCAL_MACHINE``.
  (default: None)

``regkeyalt``
  An alternate Windows registry key to try if the first key is not
  found.  The alternate key uses the same ``regname`` and ``regappend``
  semantics of the primary key.  The most common use for this key
  is to search for 32bit applications on 64bit operating systems.
  (default: None)

``regname``
  Name of value to read from specified registry key.
  (default: the unnamed (default) value)

``regappend``
  String to append to the value read from the registry, typically
  the executable name of the tool.
  (default: None)


``patch``
---------

Settings used when applying patches, for instance through the 'import'
command or with Mercurial Queues extension.

``eol``
    When set to 'strict' patch content and patched files end of lines
    are preserved. When set to ``lf`` or ``crlf``, both files end of
    lines are ignored when patching and the result line endings are
    normalized to either LF (Unix) or CRLF (Windows). When set to
    ``auto``, end of lines are again ignored while patching but line
    endings in patched files are normalized to their original setting
    on a per-file basis. If target file does not exist or has no end
    of line, patch line endings are preserved.
    (default: strict)

``fuzz``
    The number of lines of 'fuzz' to allow when applying patches. This
    controls how much context the patcher is allowed to ignore when
    trying to apply a patch.
    (default: 2)

``paths``
---------

Assigns symbolic names to repositories. The left side is the
symbolic name, and the right gives the directory or URL that is the
location of the repository. Default paths can be declared by setting
the following entries.

``default``
    Directory or URL to use when pulling if no source is specified.
    (default: repository from which the current repository was cloned)

``default-push``
    Optional. Directory or URL to use when pushing if no destination
    is specified.

Custom paths can be defined by assigning the path to a name that later can be
used from the command line. Example::

    [paths]
    my_path = http://example.com/path

To push to the path defined in ``my_path`` run the command::

    hg push my_path


``phases``
----------

Specifies default handling of phases. See :hg:`help phases` for more
information about working with phases.

``publish``
    Controls draft phase behavior when working as a server. When true,
    pushed changesets are set to public in both client and server and
    pulled or cloned changesets are set to public in the client.
    (default: True)

``new-commit``
    Phase of newly-created commits.
    (default: draft)

``checksubrepos``
    Check the phase of the current revision of each subrepository. Allowed
    values are "ignore", "follow" and "abort". For settings other than
    "ignore", the phase of the current revision of each subrepository is
    checked before committing the parent repository. If any of those phases is
    greater than the phase of the parent repository (e.g. if a subrepo is in a
    "secret" phase while the parent repo is in "draft" phase), the commit is
    either aborted (if checksubrepos is set to "abort") or the higher phase is
    used for the parent repository commit (if set to "follow").
    (default: follow)


``profiling``
-------------

Specifies profiling type, format, and file output. Two profilers are
supported: an instrumenting profiler (named ``ls``), and a sampling
profiler (named ``stat``).

In this section description, 'profiling data' stands for the raw data
collected during profiling, while 'profiling report' stands for a
statistical text report generated from the profiling data. The
profiling is done using lsprof.

``type``
    The type of profiler to use.
    (default: ls)

    ``ls``
      Use Python's built-in instrumenting profiler. This profiler
      works on all platforms, but each line number it reports is the
      first line of a function. This restriction makes it difficult to
      identify the expensive parts of a non-trivial function.
    ``stat``
      Use a third-party statistical profiler, statprof. This profiler
      currently runs only on Unix systems, and is most useful for
      profiling commands that run for longer than about 0.1 seconds.

``format``
    Profiling format.  Specific to the ``ls`` instrumenting profiler.
    (default: text)

    ``text``
      Generate a profiling report. When saving to a file, it should be
      noted that only the report is saved, and the profiling data is
      not kept.
    ``kcachegrind``
      Format profiling data for kcachegrind use: when saving to a
      file, the generated file can directly be loaded into
      kcachegrind.

``frequency``
    Sampling frequency.  Specific to the ``stat`` sampling profiler.
    (default: 1000)

``output``
    File path where profiling data or report should be saved. If the
    file exists, it is replaced. (default: None, data is printed on
    stderr)

``sort``
    Sort field.  Specific to the ``ls`` instrumenting profiler.
    One of ``callcount``, ``reccallcount``, ``totaltime`` and
    ``inlinetime``.
    (default: inlinetime)

``limit``
    Number of lines to show. Specific to the ``ls`` instrumenting profiler.
    (default: 30)

``nested``
    Show at most this number of lines of drill-down info after each main entry.
    This can help explain the difference between Total and Inline.
    Specific to the ``ls`` instrumenting profiler.
    (default: 5)

``progress``
------------

Mercurial commands can draw progress bars that are as informative as
possible. Some progress bars only offer indeterminate information, while others
have a definite end point.

``delay``
    Number of seconds (float) before showing the progress bar. (default: 3)

``changedelay``
    Minimum delay before showing a new topic. When set to less than 3 * refresh,
    that value will be used instead. (default: 1)

``refresh``
    Time in seconds between refreshes of the progress bar. (default: 0.1)

``format``
    Format of the progress bar.

    Valid entries for the format field are ``topic``, ``bar``, ``number``,
    ``unit``, ``estimate``, speed, and item. item defaults to the last 20
    characters of the item, but this can be changed by adding either ``-<num>``
    which would take the last num characters, or ``+<num>`` for the first num
    characters.

    (default: Topic bar number estimate)

``width``
    If set, the maximum width of the progress information (that is, min(width,
    term width) will be used).

``clear-complete``
    Clear the progress bar after it's done. (default: True)

``disable``
    If true, don't show a progress bar.

``assume-tty``
    If true, ALWAYS show a progress bar, unless disable is given.

``revsetalias``
---------------

Alias definitions for revsets. See :hg:`help revsets` for details.

``server``
----------

Controls generic server settings.

``uncompressed``
    Whether to allow clients to clone a repository using the
    uncompressed streaming protocol. This transfers about 40% more
    data than a regular clone, but uses less memory and CPU on both
    server and client. Over a LAN (100 Mbps or better) or a very fast
    WAN, an uncompressed streaming clone is a lot faster (~10x) than a
    regular clone. Over most WAN connections (anything slower than
    about 6 Mbps), uncompressed streaming is slower, because of the
    extra data transfer overhead. This mode will also temporarily hold
    the write lock while determining what data to transfer.
    (default: True)

``preferuncompressed``
    When set, clients will try to use the uncompressed streaming
    protocol. (default: False)

``validate``
    Whether to validate the completeness of pushed changesets by
    checking that all new file revisions specified in manifests are
    present. (default: False)

``maxhttpheaderlen``
    Instruct HTTP clients not to send request headers longer than this
    many bytes. (default: 1024)

``smtp``
--------

Configuration for extensions that need to send email messages.

``host``
    Host name of mail server, e.g. "mail.example.com".

``port``
    Optional. Port to connect to on mail server. (default: 465 if
    ``tls`` is smtps; 25 otherwise)

``tls``
    Optional. Method to enable TLS when connecting to mail server: starttls,
    smtps or none. (default: none)

``verifycert``
    Optional. Verification for the certificate of mail server, when
    ``tls`` is starttls or smtps. "strict", "loose" or False. For
    "strict" or "loose", the certificate is verified as same as the
    verification for HTTPS connections (see ``[hostfingerprints]`` and
    ``[web] cacerts`` also). For "strict", sending email is also
    aborted, if there is no configuration for mail server in
    ``[hostfingerprints]`` and ``[web] cacerts``.  --insecure for
    :hg:`email` overwrites this as "loose". (default: strict)

``username``
    Optional. User name for authenticating with the SMTP server.
    (default: None)

``password``
    Optional. Password for authenticating with the SMTP server. If not
    specified, interactive sessions will prompt the user for a
    password; non-interactive sessions will fail. (default: None)

``local_hostname``
    Optional. The hostname that the sender can use to identify
    itself to the MTA.


``subpaths``
------------

Subrepository source URLs can go stale if a remote server changes name
or becomes temporarily unavailable. This section lets you define
rewrite rules of the form::

    <pattern> = <replacement>

where ``pattern`` is a regular expression matching a subrepository
source URL and ``replacement`` is the replacement string used to
rewrite it. Groups can be matched in ``pattern`` and referenced in
``replacements``. For instance::

    http://server/(.*)-hg/ = http://hg.server/\1/

rewrites ``http://server/foo-hg/`` into ``http://hg.server/foo/``.

Relative subrepository paths are first made absolute, and the
rewrite rules are then applied on the full (absolute) path. The rules
are applied in definition order.

``trusted``
-----------

Mercurial will not use the settings in the
``.hg/hgrc`` file from a repository if it doesn't belong to a trusted
user or to a trusted group, as various hgrc features allow arbitrary
commands to be run. This issue is often encountered when configuring
hooks or extensions for shared repositories or servers. However,
the web interface will use some safe settings from the ``[web]``
section.

This section specifies what users and groups are trusted. The
current user is always trusted. To trust everybody, list a user or a
group with name ``*``. These settings must be placed in an
*already-trusted file* to take effect, such as ``$HOME/.hgrc`` of the
user or service running Mercurial.

``users``
  Comma-separated list of trusted users.

``groups``
  Comma-separated list of trusted groups.


``ui``
------

User interface controls.

``archivemeta``
    Whether to include the .hg_archival.txt file containing meta data
    (hashes for the repository base and for tip) in archives created
    by the :hg:`archive` command or downloaded via hgweb.
    (default: True)

``askusername``
    Whether to prompt for a username when committing. If True, and
    neither ``$HGUSER`` nor ``$EMAIL`` has been specified, then the user will
    be prompted to enter a username. If no username is entered, the
    default ``USER@HOST`` is used instead.
    (default: False)

``clonebundlefallback``
    Whether failure to apply an advertised "clone bundle" from a server
    should result in fallback to a regular clone.

    This is disabled by default because servers advertising "clone
    bundles" often do so to reduce server load. If advertised bundles
    start mass failing and clients automatically fall back to a regular
    clone, this would add significant and unexpected load to the server
    since the server is expecting clone operations to be offloaded to
    pre-generated bundles. Failing fast (the default behavior) ensures
    clients don't overwhelm the server when "clone bundle" application
    fails.

    (default: False)

``commitsubrepos``
    Whether to commit modified subrepositories when committing the
    parent repository. If False and one subrepository has uncommitted
    changes, abort the commit.
    (default: False)

``debug``
    Print debugging information. (default: False)

``editor``
    The editor to use during a commit. (default: ``$EDITOR`` or ``vi``)

``fallbackencoding``
    Encoding to try if it's not possible to decode the changelog using
    UTF-8. (default: ISO-8859-1)

``ignore``
    A file to read per-user ignore patterns from. This file should be
    in the same format as a repository-wide .hgignore file. Filenames
    are relative to the repository root. This option supports hook syntax,
    so if you want to specify multiple ignore files, you can do so by
    setting something like ``ignore.other = ~/.hgignore2``. For details
    of the ignore file format, see the ``hgignore(5)`` man page.

``interactive``
    Allow to prompt the user. (default: True)

``logtemplate``
    Template string for commands that print changesets.

``merge``
    The conflict resolution program to use during a manual merge.
    For more information on merge tools see :hg:`help merge-tools`.
    For configuring merge tools see the ``[merge-tools]`` section.

``mergemarkers``
    Sets the merge conflict marker label styling. The ``detailed``
    style uses the ``mergemarkertemplate`` setting to style the labels.
    The ``basic`` style just uses 'local' and 'other' as the marker label.
    One of ``basic`` or ``detailed``.
    (default: ``basic``)

``mergemarkertemplate``
    The template used to print the commit description next to each conflict
    marker during merge conflicts. See :hg:`help templates` for the template
    format.

    Defaults to showing the hash, tags, branches, bookmarks, author, and
    the first line of the commit description.

    If you use non-ASCII characters in names for tags, branches, bookmarks,
    authors, and/or commit descriptions, you must pay attention to encodings of
    managed files. At template expansion, non-ASCII characters use the encoding
    specified by the ``--encoding`` global option, ``HGENCODING`` or other
    environment variables that govern your locale. If the encoding of the merge
    markers is different from the encoding of the merged files,
    serious problems may occur.

``patch``
    An optional external tool that ``hg import`` and some extensions
    will use for applying patches. By default Mercurial uses an
    internal patch utility. The external tool must work as the common
    Unix ``patch`` program. In particular, it must accept a ``-p``
    argument to strip patch headers, a ``-d`` argument to specify the
    current directory, a file name to patch, and a patch file to take
    from stdin.

    It is possible to specify a patch tool together with extra
    arguments. For example, setting this option to ``patch --merge``
    will use the ``patch`` program with its 2-way merge option.

``portablefilenames``
    Check for portable filenames. Can be ``warn``, ``ignore`` or ``abort``.
    (default: ``warn``)
    If set to ``warn`` (or ``true``), a warning message is printed on POSIX
    platforms, if a file with a non-portable filename is added (e.g. a file
    with a name that can't be created on Windows because it contains reserved
    parts like ``AUX``, reserved characters like ``:``, or would cause a case
    collision with an existing file).
    If set to ``ignore`` (or ``false``), no warning is printed.
    If set to ``abort``, the command is aborted.
    On Windows, this configuration option is ignored and the command aborted.

``quiet``
    Reduce the amount of output printed. (default: False)

``remotecmd``
    Remote command to use for clone/push/pull operations. (default: ``hg``)

``report_untrusted``
    Warn if a ``.hg/hgrc`` file is ignored due to not being owned by a
    trusted user or group. (default: True)

``slash``
    Display paths using a slash (``/``) as the path separator. This
    only makes a difference on systems where the default path
    separator is not the slash character (e.g. Windows uses the
    backslash character (``\``)).
    (default: False)

``statuscopies``
    Display copies in the status command.

``ssh``
    Command to use for SSH connections. (default: ``ssh``)

``strict``
    Require exact command names, instead of allowing unambiguous
    abbreviations. (default: False)

``style``
    Name of style to use for command output.

``supportcontact``
    A URL where users should report a Mercurial traceback. Use this if you are a
    large organisation with its own Mercurial deployment process and crash
    reports should be addressed to your internal support.

``timeout``
    The timeout used when a lock is held (in seconds), a negative value
    means no timeout. (default: 600)

``traceback``
    Mercurial always prints a traceback when an unknown exception
    occurs. Setting this to True will make Mercurial print a traceback
    on all exceptions, even those recognized by Mercurial (such as
    IOError or MemoryError). (default: False)

``username``
    The committer of a changeset created when running "commit".
    Typically a person's name and email address, e.g. ``Fred Widget
    <[e-mail]>``. Environment variables in the
    username are expanded.

    (default: ``$EMAIL`` or ``username@hostname``. If the username in
    hgrc is empty, e.g. if the system admin set ``username =``  in the
    system hgrc, it has to be specified manually or in a different
    hgrc file)

``verbose``
    Increase the amount of output printed. (default: False)


``web``
-------

Web interface configuration. The settings in this section apply to
both the builtin webserver (started by :hg:`serve`) and the script you
run through a webserver (``hgweb.cgi`` and the derivatives for FastCGI
and WSGI).

The Mercurial webserver does no authentication (it does not prompt for
usernames and passwords to validate *who* users are), but it does do
authorization (it grants or denies access for *authenticated users*
based on settings in this section). You must either configure your
webserver to do authentication for you, or disable the authorization
checks.

For a quick setup in a trusted environment, e.g., a private LAN, where
you want it to accept pushes from anybody, you can use the following
command line::

    $ hg --config web.allow_push=* --config web.push_ssl=False serve

Note that this will allow anybody to push anything to the server and
that this should not be used for public servers.

The full set of options is:

``accesslog``
    Where to output the access log. (default: stdout)

``address``
    Interface address to bind to. (default: all)

``allow_archive``
    List of archive format (bz2, gz, zip) allowed for downloading.
    (default: empty)

``allowbz2``
    (DEPRECATED) Whether to allow .tar.bz2 downloading of repository
    revisions.
    (default: False)

``allowgz``
    (DEPRECATED) Whether to allow .tar.gz downloading of repository
    revisions.
    (default: False)

``allowpull``
    Whether to allow pulling from the repository. (default: True)

``allow_push``
    Whether to allow pushing to the repository. If empty or not set,
    pushing is not allowed. If the special value ``*``, any remote
    user can push, including unauthenticated users. Otherwise, the
    remote user must have been authenticated, and the authenticated
    user name must be present in this list. The contents of the
    allow_push list are examined after the deny_push list.

``allow_read``
    If the user has not already been denied repository access due to
    the contents of deny_read, this list determines whether to grant
    repository access to the user. If this list is not empty, and the
    user is unauthenticated or not present in the list, then access is
    denied for the user. If the list is empty or not set, then access
    is permitted to all users by default. Setting allow_read to the
    special value ``*`` is equivalent to it not being set (i.e. access
    is permitted to all users). The contents of the allow_read list are
    examined after the deny_read list.

``allowzip``
    (DEPRECATED) Whether to allow .zip downloading of repository
    revisions. This feature creates temporary files.
    (default: False)

``archivesubrepos``
    Whether to recurse into subrepositories when archiving.
    (default: False)

``baseurl``
    Base URL to use when publishing URLs in other locations, so
    third-party tools like email notification hooks can construct
    URLs. Example: ``http://hgserver/repos/``.

``cacerts``
    Path to file containing a list of PEM encoded certificate
    authority certificates. Environment variables and ``~user``
    constructs are expanded in the filename. If specified on the
    client, then it will verify the identity of remote HTTPS servers
    with these certificates.

    This feature is only supported when using Python 2.6 or later. If you wish
    to use it with earlier versions of Python, install the backported
    version of the ssl library that is available from
    ``http://pypi.python.org``.

    To disable SSL verification temporarily, specify ``--insecure`` from
    command line.

    You can use OpenSSL's CA certificate file if your platform has
    one. On most Linux systems this will be
    ``/etc/ssl/certs/ca-certificates.crt``. Otherwise you will have to
    generate this file manually. The form must be as follows::

        -----BEGIN CERTIFICATE-----
        ... (certificate in base64 PEM encoding) ...
        -----END CERTIFICATE-----
        -----BEGIN CERTIFICATE-----
        ... (certificate in base64 PEM encoding) ...
        -----END CERTIFICATE-----

``cache``
    Whether to support caching in hgweb. (default: True)

``certificate``
    Certificate to use when running :hg:`serve`.

``collapse``
    With ``descend`` enabled, repositories in subdirectories are shown at
    a single level alongside repositories in the current path. With
    ``collapse`` also enabled, repositories residing at a deeper level than
    the current path are grouped behind navigable directory entries that
    lead to the locations of these repositories. In effect, this setting
    collapses each collection of repositories found within a subdirectory
    into a single entry for that subdirectory. (default: False)

``comparisoncontext``
    Number of lines of context to show in side-by-side file comparison. If
    negative or the value ``full``, whole files are shown. (default: 5)

    This setting can be overridden by a ``context`` request parameter to the
    ``comparison`` command, taking the same values.

``contact``
    Name or email address of the person in charge of the repository.
    (default: ui.username or ``$EMAIL`` or "unknown" if unset or empty)

``deny_push``
    Whether to deny pushing to the repository. If empty or not set,
    push is not denied. If the special value ``*``, all remote users are
    denied push. Otherwise, unauthenticated users are all denied, and
    any authenticated user name present in this list is also denied. The
    contents of the deny_push list are examined before the allow_push list.

``deny_read``
    Whether to deny reading/viewing of the repository. If this list is
    not empty, unauthenticated users are all denied, and any
    authenticated user name present in this list is also denied access to
    the repository. If set to the special value ``*``, all remote users
    are denied access (rarely needed ;). If deny_read is empty or not set,
    the determination of repository access depends on the presence and
    content of the allow_read list (see description). If both
    deny_read and allow_read are empty or not set, then access is
    permitted to all users by default. If the repository is being
    served via hgwebdir, denied users will not be able to see it in
    the list of repositories. The contents of the deny_read list have
    priority over (are examined before) the contents of the allow_read
    list.

``descend``
    hgwebdir indexes will not descend into subdirectories. Only repositories
    directly in the current path will be shown (other repositories are still
    available from the index corresponding to their containing path).

``description``
    Textual description of the repository's purpose or contents.
    (default: "unknown")

``encoding``
    Character encoding name. (default: the current locale charset)
    Example: "UTF-8".

``errorlog``
    Where to output the error log. (default: stderr)

``guessmime``
    Control MIME types for raw download of file content.
    Set to True to let hgweb guess the content type from the file
    extension. This will serve HTML files as ``text/html`` and might
    allow cross-site scripting attacks when serving untrusted
    repositories. (default: False)

``hidden``
    Whether to hide the repository in the hgwebdir index.
    (default: False)

``ipv6``
    Whether to use IPv6. (default: False)

``logoimg``
    File name of the logo image that some templates display on each page.
    The file name is relative to ``staticurl``. That is, the full path to
    the logo image is "staticurl/logoimg".
    If unset, ``hglogo.png`` will be used.

``logourl``
    Base URL to use for logos. If unset, ``https://mercurial-scm.org/``
    will be used.

``maxchanges``
    Maximum number of changes to list on the changelog. (default: 10)

``maxfiles``
    Maximum number of files to list per changeset. (default: 10)

``maxshortchanges``
    Maximum number of changes to list on the shortlog, graph or filelog
    pages. (default: 60)

``name``
    Repository name to use in the web interface.
    (default: current working directory)

``port``
    Port to listen on. (default: 8000)

``prefix``
    Prefix path to serve from. (default: '' (server root))

``push_ssl``
    Whether to require that inbound pushes be transported over SSL to
    prevent password sniffing. (default: True)

``refreshinterval``
    How frequently directory listings re-scan the filesystem for new
    repositories, in seconds. This is relevant when wildcards are used
    to define paths. Depending on how much filesystem traversal is
    required, refreshing may negatively impact performance.

    Values less than or equal to 0 always refresh.
    (default: 20)

``staticurl``
    Base URL to use for static files. If unset, static files (e.g. the
    hgicon.png favicon) will be served by the CGI script itself. Use
    this setting to serve them directly with the HTTP server.
    Example: ``http://hgserver/static/``.

``stripes``
    How many lines a "zebra stripe" should span in multi-line output.
    Set to 0 to disable. (default: 1)

``style``
    Which template map style to use. The available options are the names of
    subdirectories in the HTML templates path. (default: ``paper``)
    Example: ``monoblue``.

``templates``
    Where to find the HTML templates. The default path to the HTML templates
    can be obtained from ``hg debuginstall``.

``websub``
----------

Web substitution filter definition. You can use this section to
define a set of regular expression substitution patterns which
let you automatically modify the hgweb server output.

The default hgweb templates only apply these substitution patterns
on the revision description fields. You can apply them anywhere
you want when you create your own templates by adding calls to the
"websub" filter (usually after calling the "escape" filter).

This can be used, for example, to convert issue references to links
to your issue tracker, or to convert "markdown-like" syntax into
HTML (see the examples below).

Each entry in this section names a substitution filter.
The value of each entry defines the substitution expression itself.
The websub expressions follow the old interhg extension syntax,
which in turn imitates the Unix sed replacement syntax::

    patternname = s/SEARCH_REGEX/REPLACE_EXPRESSION/[i]

You can use any separator other than "/". The final "i" is optional
and indicates that the search must be case insensitive.

Examples::

    [websub]
    issues = s|issue(\d+)|<a href="http://bts.example.org/issue\1">issue\1</a>|i
    italic = s/\b_(\S+)_\b/<i>\1<\/i>/
    bold = s/\*\b(\S+)\b\*/<b>\1<\/b>/

``worker``
----------

Parallel master/worker configuration. We currently perform working
directory updates in parallel on Unix-like systems, which greatly
helps performance.

``numcpus``
    Number of CPUs to use for parallel operations. A zero or
    negative value is treated as ``use the default``.
    (default: 4 or the number of CPUs on the system, whichever is larger)